1) Field of the Invention
The invention relates to a device for separating a flowing medium mixture into at least two fractions with differing mass density, comprising separating means for separating the flowing mixture into fractions. The invention also relates to a method for separating a flowing medium mixture into fractions with differing mass density.
2) Description of the Prior Art
The separation of a (flowing) medium mixture has many diverse applications. A medium mixture is here understood to mean a mixture of solid and/or liquid and/or gas particles of micron or submicron size dispersed in at least one liquid or gas. Examples are a gas/gas mixture, a gas/liquid mixture or aerosol, a liquid/liquid mixture, a gas/solid mixture, a liquid/solid mixture, or such a mixture provided with one or more additional fractions. The separation of a medium mixture is for instance known from various applications of liquid cleaning, (flue) gas cleaning and powder separation. Separation of fractions with a great difference in particle size and/or a great difference in mass density is relatively simple. Large-scale use is made for this purpose of processes such as filtration and screening. In the separation of fractions with a smaller difference in mass density, as is for instance the case for gas/gas mixtures, use is made of physical or chemical absorption techniques and/or separating techniques such as sedimentation and centrifugation. Certainly when processing large volumes of medium mixtures, chemical separating techniques are less economical and usually also less environmentally friendly. Separating fractions by means of sedimentation requires time and, when processing larger volumes of medium mixture, makes it necessary to make use of voluminous reservoirs, which is, among other things, expensive.
A known device is described in NL1026299. The known device comprises separating means in the form of a rotating assembly of feed channels for rotating the flowing mixture for separating, a feed for the medium mixture to be separated connecting to the rotating means, and outlets connecting to the rotating means for discharging the fractions of the separated medium mixture. In a rotating feed channel the heavier fraction of the mixture for separating is moved further outward towards the wall thereof than the lighter fraction under the influence of the centrifugal force, thus resulting in a separation. Separation selectivity and efficiency however can be improved further.
The present invention has for its object to provide a device and method capable of providing an increased selectivity for the fractions to be separated.